Positive shutoff variable recoil mechanism



April 28, 1964 R. A. MAGNUSON 3,130,640

POSITIVE SHUTOFF VARIABLE RECOIL MECHANISM Filed April 17, 1962 e Sheets-Sheet 1 FIG. I

- FIG. 2

INVENTOR. ROLAND A. MAGNUSON ijfida'mlg ad F V 2. 7

6 Sheets-Sheet 2 INVENTOR. ROLAND MAG'NUSON BY I 1,41 ,51 w -m R, A. MAGNUSON April 28, 1964 POSITIVE SHUTOF'F VARIABLE RECOIL MECHANISM Filed April 17, 1962 April 28, 1964 R. A. MAGNUSON POSITIVE SHUTOFF VARIABLE RECOIL MECHANISM 6 Sheets-Sheet 3 Filed April 17, 1962 FIG. 4

INVENTOR. ROLAND MAGNUSON April 28, 1964 R. A. MAGNUSON POSITIVE SHUTOFF VARIABLE RECOIL MECHANISM 6 Sheets-Sheet 4 Filed April 17, 1962 FIG.6

INVENTOR. ROLAND A. MAGNUSON v BY 1 1. mam; Q-Za MYS HM. g

April 28, 1964 R. A. MAGNUSON 3,130,640

POSITIVE SHUTOFF' VARIABLE RECOIL MECHANISM Filed April 17, 1962 6 Sheets-Sheet 5 FIG. 7

INVENTOR. ROLAND A. MAGNUSQN' BY 7 April 28, 1964 R. A. MAGNUSON 3,130,640

POSITIVE SHUTOFF' VARIABLE RECOIL MECHANISM Filed April 17, 1962 6 Sheets-Sheet 6 INV EN TOR.

- ROLAND A. MAGNUSON BY 1.}. mm 62.4% we mg,

United States Patent 3,130,640 POSITIVE SHUTOFF VARIABLE RECOIL MECHANISM Roiand A. Magnuson, Seattle, Wash., assignor, by mesne assignments, to the United States of America as represented by the Secretary of the Army Filed Apr. 17, 1962, Ser. No. 188,288 3 Claims. (Cl. 8943) ing fluid. On piston movement the braking fluid passes from the high pressure side of the piston to the low pressure side by way of identical constant deceleration orifices formed in the head of the piston. These orifices are progressively throttled as recoil stroke occurs by the helical edges of fluid flow channels formed in a control rod mounted in the chamber.

The movement of the braking fluid through the orifices dissipatesrthe kinetic energy of the moving barrel. The progressive closing of the orifices will keep the chamber pressure constant and a constant deceleration of the barrel throughout recoil stroke results. The recoil stroke will be complete when orifice closure is complete.

' At low barrel elevations the recoil mechanism. must dissipate a large percentage of the energy imparted to the barrel to prevent undesirable weapon carriage motion,

and possible upset. This can be accomplished by having constant barrel deceleration over a long recoil stroke. However, at higher barrel elevations the recoil must be shortened because of space limitations behind the barrel and to prevent the barrel from striking the carriage. A

constant barrel deceleration over a controlled shortened stroke will prevent contact between the barrel and supporting carriage. Recoil forces not absorbed by the recoil control mechanism are imparted to the vehicle suspension system or other support. Stroke length is varied by rotating the control rod asthe barrel is elevated to partially close the orifices before firing. This. shortens the stroke since less stroke is required to reach the point at which the helical edges completely close the orifices. Thus, control rod rotation isequivalentto piston translation. 7

It is therefore an object of the present invention to provide arecoil control mechanism which will constantly j decelerate a recoiling gun barrel and positively limit the recoil stroke for all barrelelevations.

Another object of the present. invention is to provide a recoil control device which eifectively varies the recoil stroke as a function of barrel elevation.

A further object of the present invention is to a recoil control device which will positively and consistently control recoil stroke.

Objects and advantages other than those set forth will be apparent from the following description when read in conjunction with theaccornpanying drawing in which:

FIG. 1 is a sehematic view of the artillery piece with the control rod actuating mechanism.

FIG. 2 is a schematic view of the recoil mechanism showing the barrel, recoil cylinder, piston and the control rod.

FIG. 3 is a sectional View of the recoil cylinder, the control rod and piston.

FIG. 4 is a side elevational view of the control rod.

provide 3,139,546 Patented Apr. 28, 1964 FIG. 5 is a cross sectional view taken along lines 55 of FIG. 4.

FIG. 6 is a cross sectional view taken along lines 6--6 of FIG. 4,

FIG. 7 is a perspective view showing details of the piston and the control rod.

FIG. 8 is a side view of the piston head showing one of the constant deceleration orifices.

Referring more particularly to the drawing, wherein like reference characters refer to corresponding parts, FIG. 1 shows a gun barrel I mounted to' slide on gun cradle 2. This cradle ispivoted to a top carriage 3 by trunnions 4 in order that the barrel may be elevated. In turn, the top carriage is rotatably mounted on a Vertical axis to a bottom carriage 5 in order that the barrel may be traversed. The bottom carriage is seated on a vehicle platform or other support 6 and transmits firing. stresses not otherwise dissipated to that platform or support. K

Secured in the cradle is a cylinder 7 which contains an oil or other braking fluid. As shown in FIG. 3, the cylinder is closed at each of its ends by head members 25 and 26. Retainer rings 28 and 29 secured to the cylinder 7 by screws 35, hold the head members on the cylinder. Appropriate seals 27 are provided to prevent any leakage of the oil between the head member spand the walls of the cylinder. Reciprocally ,mounted in the cylinder is a piston 8. This piston isforrned from a pistonrod 9 and an attached headlt). Oneend of the piston rodis secured to yoke 11 by removable pin 32 and the yoke is 4 in turn fixed to the gun barrel .by'a gun lug 12 andhut 13.

The piston head has formed therein two identical sharpedged orifices lit-14 which are on opposite sides of the head. Each orifice has an elongated .legportion' l6 and a a communicating foot portion 17. Outer edges Is and 15 of each orificeare disposed substantiallyat right angles with respect to each other, while theinner edge; 18 is curved and intersectsthe outer extremities of edges 15, 15' as shown in FIG. 8.. The foot portion may torm the top of theorifice onone side of the head and the bottom of the orifice on the other side of the head. 7 v

The orifice areas and shapes in the piston headlt) of the present invention are .designed' to insure that. the fluid pressure in cylinder 7 is maintained substantially constant throughout recoil for. all ranges of barrel elevation. v V V V The piston head and rod are hollowed out to form a housing for a cylindrical control rod 20. The control rod has two fluid flow channels 21 formed therein which extend along the major portion of the control rod. Each channel is formed between the straight edge 22 and the helical edge 23 as shown in FIGS. 4.to 6. The control rod and piston are coaxially mounted in the recoil cylinder. 7 K When the piece is fired the projectile and barrell are propelled in opposite direction by equal and opposite forces, and the piston is moved longitudinally in. the cylinder on thecontrol rod. When at low gun elevations, and at the. commencement of long recoil strokes, the short edge of each orifice is substantially aligned with the helical edge of each channel 21. Onpistonmovement oil will be throttled through theorifices into the fluid flow channels todissipate energy imparted to the barrel.

As this piston movement takes place, thehelical edges on the rod graduallyrestrict the orifice openings in the piston head. These orifices willdecrease in size progressively with the stroke and at a rate so that constant cylinder pressure is maintained throughout the stroke. This is. accomplished by designing the orifice area as a vfunction of the stroke rather than a function of energy consumption. Since constant cylinder pressure is maintained the restraining force will be constant and deceleration of the gun barrel will be constant. Obviously the magnitude of the restraining force must be compatible with the gun mount or vehicle from the standpoint of overturning stability. When the orifices are completely closed, there can be no further relative movement between the barrel and the cylinder due to the incompressibility of the braking fluid.

T o prevent the galling of piston rod 9 and the bore in the head member 26, grooves 41 are turned in the head member to assure uniform distribution of fluid forces about the piston rod. The lands between the grooves may be coated with a suitable lubricant if desired tolessen friction. Suitable seals 27' prevent oil leakage between rod 9 and head 26.

A replenisher (not shown) may be connected to the recoil cylinder through suitable openings 7 to serve as a reservoir for excess braking fluid when the fluid is expanded by heat developed during firing or increased atmospheric temperature. Also, the replenisher keeps the recoil cylinder filled when the fluid in the cylinder contracts because of falling temperatures.

During the recoil stroke, the orifices 141-4 are closed by the simple longitudinal movement of the piston on the control rod. It is therefore obvious that wear is at a minimum and the recoil control will be constant even after long usage.

The end of control rod is provided with an external spline 24 which forms a seat for segment gear 34 Threaded nut 24' fastens gear 30 to the control rod. The teeth of this gear intermesh with the teeth of segment gear 31 which is rigidly secured to variable recoil cam 33 by rod 34 as shown in FIG. 2. This cam is rotatably mounted in housing 17 on gun cradle 2. As shown in FIG. 2, this cam has a curved slot 18. The cam is linked to top carriage 3 by longitudinally slidable cam actuating rod 19 and connecting rod 20'. One end of rod 19 extends into the cam and carries a pin 21 which rides in the cam slot. The other end of rod 19 is pivotally secured to one end of connecting rod 20'. The other end of the connecting rod is pivotally secured to top carriage 3. As the barrel 1 and cradle 2 are elevated or depressed by elevating arc 39 and handle 40, the actuating rod 19 moves forward or backward. The movement of pin 21' in slot 18 rotates variable recoil cam 33 which by means of the gear segments rotate the control rod. Thus, on barrel elevation, when short recoil stroke is needed, the helical edges 23 23 will move from substantial alignment with the short horizontal edges of each orifice to a position between the short horizontal edge and the longer edge of each orifice to partially close the orifices at commencement of the short recoil stroke. the stroke will be shorter than the stroke of the gun at lower elevations since a shorter distance has to he traveled by the piston before there is complete orifice closure. The shortened stroke prevents the recoiling barrel from striking the supporting platform or projections thereon. Due to the connection between the control rod and upper carriage, the amount of orifice closure will be a function of the gun elevation and the higher the elevation the shorter the stroke.

It is contemplated that other operative means may be substituted for the recoil cam 133 and the associated means for rotating the control rod relative to the piston as the barrel is elevated. Examples of alternative control rod rotating devices can be found in U.S. Patents 755,418 to Voller and 818,730 to Yingling.

When the recoil action ceases a counter recoil device (not shown) which gains energy at the expense of the energy possessed by the recoiJing barrel returns the barrel to battery position. As shown in FIG. 3, the rear end of the control rod acts as a butter at the end of the counter recoil motion. Bv throttling a small amount of When the elevated gun is fired,

fluid through throttling grooves formed in the rod to the recoil cylinder, the barrel is decelerated and eased into battery position.

Although developed specifically for artillery application, this recoil mechanism may be utilized in any mechanical system requiring regulated stroke and constant deceleration of a moving mass.

From the foregoing, it will be seen that this invention attains all of the objects set forth, together with other advantages which are obvious and inherent to the structure. It is to be understood that all matter set forth above or shown in the accompanying drawing is to be interpreted as illustrative and not in a limiting sense.

The invention having been described, what is claimed is:

1. In a recoil control device for constantly decelerating a recoiling gun barrel, a chamber having braking fluid therein, a piston rod longitudinally movable in said chamber, means securing said piston rod to a movable gun barrel, a head having irregular shaped orifices therein secured .to said rod, said orifices adapted to permit braking fluid to flow from one side of said head to the opposite side of said head, a rotatable control rod mounted coaxially within said piston rod, said piston rod being slidably mounted on said control rod, said control rod having a fluid flow channel formed therein for each of said orifices, each of said channels being defined by a straight edge and an opposed helical edge, said helical edges providing means to progressively close said orifices at a rate as the piston rod and head move from one end of said chamber to the other on gun barrel recoil to maintain constant fluid pressure in said cylinder, rotating means connected to said control rod for rotating said control rod to automatically partially close said orifices as the gun barrel is elevated from a horizontal position to shorten recoil of the elevated gun barrel.

2. In a recoil control device for constantly decelerating a recoiling gun barrel, a recoil chamber having a braking fluid therein, a piston having an enlarged head and a hollow rod reciprocally movable in said chamber, said piston head having an irregular shaped orifice on either side thereof to permit the braking fluid to flow from one side of said head to the other, a rotatable control rod mounted in said cylinder and extending into said piston rod and head, said piston rod and said control rod being coaxially mounted in said chamber, said control rod being formed with a channel therein for each of said orifices, each of said channels being defined by a helical edge and an opposed straight edge, said helical edges providing means on barrel recoil for throttling fluid flow through said orifices by progressively restricting said orifices at a rate to maintain substantially constant fluid pressure in said chamber, said control rod extending from one end of said chamber, rotatable cam means secured to said control rod to turn said rod as the gun is elevated so that said orifices are partially closed by said helical edges.

3. The device defined in claim 2 wherein said chamber is formed with first and second head members, said second head member being formed with a bore therein, said piston rod extending through said bore, the walls of said second head member defining said bore being formed with spaced grooves therein to assure uniform distribution of fluid forces about the piston rod to prevent scoring of the bore and piston rod on barrel recoil.

References Cited in the file of this patent UNITED STATES PATENTS 

1. IN A RECOIL CONTROL DEVICE FOR CONSTANTLY DECELERATING A RECOILING GUN BARREL, A CHAMBER HAVING BRAKING FLUID THEREIN, A PISTON ROD LONGITUDINALLY MOVABLE IN SAID CHAMBER, MEANS SECURING SAID PISTON ROD TO A MOVABLE GUN BARREL, A HEAD HAVING IRREGULAR SHAPED ORIFICES THEREIN SECURED TO SAID ROD, SAID ORIFICES ADAPTED TO PERMIT BRAKING FLUID TO FLOW FROM ONE SIDE OF SAID HEAD TO THE OPPOSITE SIDE OF SAID HEAD, A ROTATABLE CONTROL ROD MOUNTED COAXIALLY WITHIN SAID PISTON ROD, SAID PISTON ROD BEING SLIDABLY MOUNTED ON SAID CONTROL ROD, SAID CONTROL ROD HAVING A FLUID FLOW CHANNEL FORMED THEREIN FOR EACH OF SAID ORIFICES, EACH OF SAID CHANNELS BEING DEFINED BY A STRAIGHT EDGE AND AN OPPOSED HELICAL EDGE, SAID HELICAL EDGES PROVIDING MEANS TO PROGRESSIVELY CLOSE SAID ORIFICES AT A RATE AS THE PISTON ROD AND HEAD MOVE FROM ONE END OF SAID CHAMBER TO THE OTHER ON GUN BARREL RECOIL TO MAINTAIN CONSTANT FLUID PRESSURE IN SAID CYLINDER, ROTATING MEANS CONNECTED TO SAID CONTROL ROD FOR ROTATING SAID CONTROL ROD TO AUTOMATICALLY PARTIALLY CLOSE SAID ORIFICES AS THE GUN BARREL IS ELEVATED FROM A HORIZONTAL POSITION TO SHORTEN RECOIL OF THE ELEVATED GUN BARREL. 